Lightweight, extraordinarily strong materials enable technology that will significantly impact advanced manufacturing and product designs in areas such as aerospace, transportation and renewable energy applications. High strength-to-weight-ratio materials for parts manufacturing in transportation will significantly reduce fuel consumption, while still complying with current safety standard levels. Typical industrial high-strength composites are comprised of carbon fibers dispersed in a matrix polymer. Progress in nanofiber processing, including heteroatom doping, nanofiber growth and assembly methodologies, spinning technologies (wet and dry), centrifugal (forced) methods, electro-spinning, fiber/fabric/composite processing using nanoparticle inclusive pyrolysis (PAN hollow carbon fibers) and MEMS weaving of nanofibers have enabled many desirable mechanical and processing properties. A significant amount of research in the area of high strength and low-weight composites has focused on the fiber reinforcements and the interfaces within the composite. In this regard, an important and tunable parameter is the matrix resin used to disperse the carbon fibers. Effective resins require thermal stability, high dimensional stability and modulus, tough, ductile mechanical properties, solvent resistance and adhesion with the filler. Identifying polymer resins that meet these essential criteria are often considered one of the main bottlenecks of advanced manufacturing. Hybrid polymers possessing both functionalities, rigidity and solution-solubility, allows access to resins that meet these requirements through careful selection of the polymer composition.
Incorporation of porous fibers into a polymer matrix is an ideal way to reduce the weight of a composite structure. However, the ability to impart porosity to the matrix material would be highly desirable as well. For such applications, the porosity should be significantly smaller that the fibers that reinforce the material so that the pores do not form defects or concentrate stress, which might lead to catastrophic failure. Given these criteria, traditional blow molding strategies are not applicable.
There is a need for methods of making strong nanoporous materials that may be used as part of a fiber matrix.